Your period can come anytime during the fourth week, even on the last day. Just start your new pack when it is due no matter what your body is doing. On occasion, you may skip a period or just have light spotting and that is all. If you miss two periods in a row, you should test and consult the gynecologist.

By Kaismama telling you a 1% chance of pregnancy if taken correctly she means every single day at around the same time of day (give or take an hour each way of the time you pick) the more you vary from this, the less effective the pill becomes. If you are often late taking pills or you miss pills and do not use back up, the percentage drops to 94-96% the more you miss, the lower it can drop. Average use is about 96-98% effective (this is with the occasional late pill or missed pill made up and using back up for seven days) If you take them perfectly effectiveness can be 99.9%. Taking antibiotics can also decrease effectiveness and condoms should be used as back up the whole time you are on the antibiotics and for seven days after you finish the last one. This is one of the biggest reasons for birth control pill failure-not using back up when appropriate and missing doses.

No method is 100% but the pill, when taken perfectly is as close as you can get! Stress about being pregnant can delay your period too so if you are doing a good job of taking your pill, dont worry, you are well protected.:-)